A molecule of low abundance from bovine small intestine was identified as a potent immunostimulant and associating with the natural suppression of cancer in the intestinal tract. The protein originates from an endemic gut protozoan, Eimeria spp., and is homologous to the antigen 3-1E previously isolated from the avian apicomplexan E. acervulina (Rosenberg et al., Int. J. Cancer 2005; 114: 756-765). Methods of purifying this molecule and its use in immune stimulation were previously disclosed (see, e.g., PCT publication WO 2005/010163 and PCT publication WO 2005/010040). A similar 19-kDa antigen has been identified as being a profilin-like protein (Fetterer et al., J. Parasitol. 2004; 90(6): 1321-8).
Antibiotics have been successfully utilized to treat various bacterial infections in subjects. Viral infections in subjects, however, have been more challenging to treat or prevent. Even though there are several anti-viral agents available on the market, most often these agents do not provide a successful treatment or prevention. There remains a need in the field for a broad-spectrum anti-viral agent that can treat/prevent/cure many different viral infections in subjects through activating the immune system. The present invention addresses this and other needs in the art.